Update notes for submitted changes

* Fix signal strength indicator.
* 32 bit int shifted by an amount not in the range -31..31 (FindBugs)
* Fix another duplicate response bug in AT+CSCS handling.
* AtPhonebook handleCpbsCommand was incorrectly sending two responses to some requests (one inside the swtich statement, then repeating it after breaking out of the switch statement). This broke phonebook sync with Audi 2G MMI car kit. Signed-off-by: Nigel Hannam <nigel@hannam.eu>